Clear barrel cartridge fuse



Sept. 27, 1966 R. E. NEFF 3,275,772

CLEAR BARREL CARTRIDGE FUSE Filed Deo. 25, 1964 INVENTOR.

United States Patent O 3,275,772 CLEAR BARREL CARTRIDGE FUSE Robert E. Neff, Orlando, Fla., assigner to Devices Inc., Orlando, Fla., a corporation of Florida Filed Dec. 23, 1964, Ser. No. 420,491 Claims. (Cl. 200-129) The present invention relates to an improved electrical fuse, and more particularly relates to the construction of an improved and easily constructed fuse made of a transparent plastic material in the form of a barrel or hollow cylinder and having metal ends, so that the over-all shape resembles that of a cartridge. The invention, therefore, relates to a clear barrel-shaped cartridge fuse comprising inner and outer hollow cylindrical bodies, a fuse body disposed in the inner cylindrical body, metal caps disposed at each end of the -outer cylindrical body, and forming circuit contact means for the ends of an electrical circuit which includes the fuse body disposed throughout the length of the inner cylindrical body.

It has lbeen known in the prior art that many times the fuse body when it has been subjected to excessive or heavy electrical currents beyond the rating of the fuse so that the fuse body tends to burn or attains a condition known as blown, the fuse body often doubles up. The doubling up of the fuse body or the links forming the fuse body is found to be the most frequent cause of res resulting from ini-perfectly burned fuses. The `doubling up is often caused by the heat resulting from the excessive current flow, and the heat causes the fuse body to become elongated so that it can double up without causing any cessation of the current flow through the fuse. -It has been found that when an inner hollow cylindrical body is provided within the fuse cartridge, and the fuse body is transversely disposed between the ends of the inner hollow cylindrical body, the fuse Ibody or the links of the fuse body are not caused to double up in the fuse in detection of the excessive currents, and because of the c-onstruction of the inner cylindrical body, the fuse is more rapidly caused to break the current path between the ends lof the cartridge to which the fuse is connected in circuit.

It is therefore an object of the present invention to provide a transparent fuse construction, which is moistureproof, which provides instant detection of the fuse condition, which provides means to prevent doubling up of the fuse body when blown or conducting excessive currents, and which 4may be either of the non-reusable or renewable type of fuse.

A further object of the invention is to provide a fuse that cuts maintenance costs, a fuse which is tamper-proof, a fuse which is self-indicating that it is either in the blown or new condition, and which does not require the use of additional equipment such as fuse testers.

An important and paramount object of the invention is that there is provided a device which is transparent and readily displays the condition or state of the fuse body in the circuit to which it may be connected.

A further object of the present invention is to provide a mechanical construction for a fuse of a sealed, controlrated flip-out insert cartridge which is used in the renewable type fuse -as a rell, but sealed in the one-time or throwaway type cartridge. Thus the cartridge may be a portion of a larger fuse system in which the fuse may be used.

A further advantage of the present invention is that the use of fuses can be detected by supervisory personnel or safety department personnel at a glance so that it is apparent that maintenance personnel have not doubled up on the links in the fuse. This as a result of the present invention being directed t-o a construction elimi- ICC nating the capability of doubling up of links in fuses without being detected by supervisory or safety personnel.

Other objects and advantages will be apparenty from a detailed description of the particular embodiment of the invention. In the description, reference is made to the accompanying drawings of which:

FIGURE 1 is a generally perspective view of a preferred embodiment of the clear barrel cartridge fuse of the present invention;

FIGURE 2 is a cross-sectional, side elevational view of a renewable type of fuse in accordance with the concepts of the present invention; l

FIGURE 3 shows a metal cap shown partially in crosssection having an internal threaded portion for engaging a threaded end of a cylindrical body;

FIGURE 4 shows a detailed view of an end of the inner cylindrical body and a metal end thereof;

FIGURE 5 shows the outer and inner threaded portions of an end of the outer hollow cylindrical body;

FIGURE 6 shows a cross-sectional view taken along -lines 6 6 of FIGURE 2;

FIGURE 7 shows an embodiment of the invention in which the fuse body is shown as being blown;

FIGURE 8 shows a mo'died construction of the preferred embodiment of the invention in which the inner hollow cylindrical body is diagonally or transversely disposed and shown in -cross-section;

FIGURE 9 is a cross-sectional view taken along lines 9-9 of FIGURE 8; and

FIGURE 10 shows an outside side elevational view in reduced scale of the embodiment generally shown in FIGURE 8.

Referring now to the drawings, there is shown a clear barrel cartridge fuse 10 in FIGURES l-7 having -a main portion which is a hollow cylindrical body 12 shown as having a uniform outside diameter throughout and constructed of transparent plastic material. At the ends of the hollow cylindrical body are metal caps 14, 14 constructed to threadedly engage the ends 16, 16 of the hollow cylindrical holding member or sleeve 22. As more particularly shown in FIGURES 2 and 5, there is an externally threaded portion 20 which receives a mutually engaging threaded portion of the holding member 22, 22 shown as having a uniform outside diameter throughout generally identical to that of the cylinder body 12 and that ris axially disposed of the hollow cylindricalbody 12 and serves to coaxially locate the inner cylindrical body 26 with its metal ends 28, 28, said metal ends 28, 28 being xedly secured to the metal caps 14, 14, respectively.

Within the inner hollow cylindrical body, there is a fuse body 34 which extends throughout the length of the inner cylindrical body and connects electrically with the metal caps 14, 14 so that there is a complete series circuit cornpleted between one metal cap 14 and the other metal cap 14 through the fuse body. The inner cylindrical body is transparent and similarly constructed of the Iplastic material so that it is observable whether the fuse body is intact or has been blown, as is demonstrated and illustrated in the embodiment shown in FIGURE 7. FIGURE 7 shows the fuse body 36 to be in a blown condition.

At the ends of the metal caps 14, 14 are turning means shown as `a. web 40` at one end and a screw driver receiving means `42 at the other end, so that the metal caps may be tightened or loosened as desired so that metal caps may In FIGURES 8, 9 and 10,'there is shown a further preferred embodiment that demonstrates that the inner cylindrical body 26a may be tilted in relation to the outer hollow cylindrical body 12a so that it is diagonally disposed within the hollow thereof.

The metal caps 14a, 14a forming the ends of the clear barrel cartridge fuse formed by the outer hollow cylinder 12a of transparent material are conveniently soldered or fused onto each other so that a tight and integral, sturdy and workable unit is devised.

The fuse body is in vcoaxial alignment along the inner portion of the inner hollow cylindrical lbody 26a, the fuse tbody being shown as 34a. The ends of the fuse body are joined or positioned upon the metal portion of the metal caps 14a, 14a, respectively, so that when the fuse operation or the forming and securing of the metal caps 14a, 14a onto the outer hollow cylinder 12a is accomplished, the ends of the fuse body 34a are soldered or welded onto and fused with the adjacent accompanying parts. In this manner, a secure and workable product is produced, and the interior of the clear barrel cartridge fuse is devoid of receiving any moisture from the exterior, so that there is a water-proof -or moisture-proof product devised. When the fuse is blown, the feature of the clear barrel cartridge is such that instantaneous detection of the blown state or condition is observed and the fuse may then be conveniently replaced.

By means of the construction of the embodiments shown in FIGURES 8, 9 and 10, FIGURE 10 being a reduced size View of the embodiment, there is no possibility of tampering or reconstructing the components so that an improper fuse body would be inserted into the interior of the inner hollow cylinder 26a.

`It should be understood that the specific apparatus herein described and illustrated in the preferred embodiments, is intended to be representative only, as many changes may be made therein without departing from the clear teachings of the invention. Accordingly, reference should lbe made to the following claims in determining the full scope of the invention.

What is claimed is:

1. A clear barrel cartridge fuse comprising a hollow cylindrical body constructed of transparent plastic material, a metal cap disposed at each end and fused to the cylindrical body at each end, an inner cylindrical body transversely disposed within the hollow cylindrical body along its length and constructed of transparent plastic material, said inner cylindrical body having a fuse body disposed along the length of the inner cylindrical body and positioned therein, said fuse body forming a portion of an electrical circuit formed between the said metal caps, said metal caps having an inner threaded portion engaged to the ends of the hollow cylindrical body by an annular sleeve, said metal caps having an inner cap surface defined by an annular recess, said inner threaded portion of the metal caps terminating with the annular recess, said annular formed inner cap surface engagingly mating with the end of the metal ends of said inner cy-lindrical lbody, said annular metal sleeve being of reduced size and having uniform outside idiameter throughout substantially identical with the uniform outside diameter of the hollow cylindrical body, said sleeve threadedly engaging the outer portion of the ends of the hollow cylindrical body for xedly disposing the outer ends of the inner cylindrical body securely to a threaded annular inner surface of the adjacent metal caps thereof.

2. The invention according to claim 1 wherein a central portion of the fuse body is reduced in its transverse cross-sectional area to provide a reduced current path and perform the function as an electrical fuse.

3. The invention according to claim 1 wherein said fuse body is disposed diagonally with respect to the hollow cylindrical body.

4. The invention according to claim 1 wherein solder is used to ydispose the fuse body to the metal ends at the ends of the inner cylindrical body and complete the electrical path between the metal caps, as well as form a structural holding means for the component parts of said clear barrel cartridge fuse.

5. The invention according to claim 1 wherein said annular sleeve of reduced size has an inwardly projecting annular ange for engaging the end of the inner cylindrical body.

References Cited by the Examiner UNITED STATES PATENTS 737,282 8/1903 Sachs 200-132 X 1,226,151 5/1917 Weinberg 200-132 X 1,388,269 8/1921 Kramer 200-132 1,788,768 1/1931 La Mar 200-132 1,828,277 10/1931 Bennett 200-131 1,856,701 3/1932 Gerdien 20G-135 X 2,341,865 2/1944 Hermann 200--135 2,458,307 1/1949 Smith 200-120 2,827,532 3/1958 Kozacka 200-135 X 2,936,014 5/1960 Kraus et al 151-14 X FOREIGN PATENTS 21,973 i 9/1961 East Germany. 580,759 9/ 1946 Great Britain. 259,917 6,/ 1926 Italy.

BERNARD A. GILHEANY, Primary Examiner. H. B GILSON, Assistant Examiner. 

1. A CLEAR BARREL CARTRIDGE FUSE COMPRISING A HOLLOW CYLINDRICAL BODY CONSTRUCTED OF TRANSPARENT PLASTIC MATERIAL, A METAL CAP DISPOSED AT EACH END AND FUSED TO THE CYLINDRICAL BODY AT EACH END, AN INNER CYLINDRICAL BODY TRANSVERSELY DISPOSED WITHIN THE HOLLOW CYLINDRICAL BODY ALONG ITS LENGTH AND CONSTRUCTED OF TRANSPARENT PLASTIC MATERIAL, SAID INNER CYLINDRICAL BODY HAVING A FUSE BODY DISPOSED ALONG THE LENGTH OF THE INNER CYLINDRICAL BODY AND POSITIONED THEREIN, SAID FUSE BODY FORMING A PORTION OF AN ELECTRICAL CIRCUIT FORMED BETWEEN THE SAID METAL CAPS, SAID METAL CAPS HAVING AN INNER THREADED PORTION ENGAGED TO THE ENDS OF THE HOLLOW CYLINDRICAL BODY BY AN ANNULAR SLEEVE, SAID METAL CAPS HAVING AN INNER CAP SURFACE DEFINED BY AN ANNULAR RECESS, SAID INNER THREADED PORTION OF THE METAL CAPS TERMINATING WITH THE ANNULAR RECESS, SAID ANNULAR FORMED INNER CAP SURFACE ENGAGINGLY MATING WITH THE END OF THE METAL ENDS OF SAID INNER CYLINDRICAL BODY, SAID ANNULAR METAL SLEEVE BEING OF REDUCED SIZE AND HAVING UNIFORM OUTSIDE DIAMETER THROUGHOUT SUBSTANTIALLY IDENTICAL WITH THE UNIFORM OUTSIDE DIAMETER OF THE HOLLOW CYLINDRICAL BODY, SAID SLEEVE THREADEDLY ENGAGING THE OUTER PORTION OF THE ENDS OF THE HOLLOW CYLINDRICAL BODY FOR FIXEDLY DISPOSING THE OUTER ENDS OF THE INNER CYLINDRICAL BODY SECURELY TO A THREADED ANNULAR INNER SURFACE OF THE ADJACENT METAL CAPS THEREOF. 